How to form a tapered stamp from an SVG
This result can be achieved easily using basic operations.


Connect parts of your shape, so it only has one edge (select 4 vertices and press F and repeat)  
Connect it to a circle (or your handle)
Add some ridges and move your shape upwards to taper it.


Make one outside edge and connect it to a circle (or other shape)



Extrude it to make a handle (unless you already have one)



Add some ridges and move the shape upwards, it will taper nicely.